This proposal is an attempt to resolve the window.opener.location.href issue with cross-origin (and same-origin UGC?) navigations when target="_blank". This issue has been discussed previously[1] and a bug[2] in chromium has existed since 2013. Besides using "rel=noreferrer" or setting window.opener=null via javascript there appears no clean solution to this problem.

I propose that a new rel=newcontext attribute be added which can be used to inform user agents that the navigation should be done in a new browsing context and, as a result, window.opener should be set to null. Many publishers wish to allow a referrer to be sent and the Referrer Policy[3] is moving towards a spec where there is more granular control over the document-level and even the link-level value of Referer (sic). Many sites wish to send the origin, for instance, and in these cases they cannot use "rel=noreferrer". This leaves them only Javascript to deal with this issue. I think there should be a way to do this via HTML only.

Here is a quick summary and demo of the issue[4].

I've prepared a PR to the spec here[5].

[1] https://lists.w3.org/Archives/Public/public-whatwg-archive/2015Jan/0002.html
[2] https://code.google.com/p/chromium/issues/detail?id=168988
[3] http://w3c.github.io/webappsec/specs/referrer-policy/
[4] http://hardstatics.com/thrower.html
[5] https://github.com/w3c/html/pull/22